streaming

commit 2611483e348541c03d648c6455415a50298bda3e
parent ff1c5bccc7b8e868d34831a859fa962c408f104a
Author: Oliver Lowe <o@olowe.co>
Date:   Sun, 30 Jun 2024 12:58:43 +1000

sdp: implement parsing some (not all) optional fields

Diffstat:
M
sdp/sdp.go
 | 
48
+++++++++++++++++++++++++++++++++++++++---------
M
sdp/sdp_test.go
 | 
26
++++++++++++++++++++++++--

2 files changed, 63 insertions(+), 11 deletions(-)
diff --git a/sdp/sdp.go b/sdp/sdp.go
@@ -18,10 +18,12 @@ type Session struct {
 	Origin  Origin
 	Name    string
 
-	Info    string
-	URI     *url.URL
-	Email   *mail.Address
-	Phone   string
+	Info  string
+	URI   *url.URL
+	Email *mail.Address
+	// TODO(otl): can we do any sanitisation here? at least delete spaces or something...?
+	// The number "+1 617 555-6011" is semantically equal to "+16175556011"
+	Phone string
 	// TODO(otl): add rest of fields
 }
 
@@ -31,13 +33,17 @@ type Origin struct {
 	Version     int
 	Network     string // TODO(otl): only "IN" is valid... so int type?
 	AddressType string // TODO(otl): only "IP4", "IP6" valid... new int type?
-	Address     string
+	Address     string // IPv4, IPv6 literal or a hostname
 }
 
+var fchars = [...]string{"i", "u", "e", "p"}
+
 func ReadSession(rd io.Reader) (*Session, error) {
 	sc := bufio.NewScanner(rd)
 	next := "v"
 	var session Session
+First:
+	// read the mandatory fields first
 	for sc.Scan() {
 		if sc.Text() == "" {
 			continue // TODO(otl): empty lines allowed?
@@ -72,25 +78,49 @@ func ReadSession(rd io.Reader) (*Session, error) {
 				return nil, fmt.Errorf("empty name")
 			}
 			session.Name = v
+			break First
+		default:
+			return nil, fmt.Errorf("expected key %q, found %q", next, v)
+		}
+	}
+
+	// Time for the optional fields. We keep a slice...
+	// TODO(otl): document in plain language what's going on here.
+	onext := fchars[:]
+	for sc.Scan() {
+		if onext == nil {
+			break
+		}
+		if sc.Text() == "" {
+			continue // TODO(otl): empty lines allowed?
+		}
+		k, v, found := strings.Cut(sc.Text(), "=")
+		if !found {
+			return nil, fmt.Errorf("parse field %q: missing %q", next, "=")
+		}
+		switch k {
 		case "i":
 			session.Info = v
-			// TODO(otl): what do we expect next?
+			onext = fchars[1:]
 		case "u":
 			u, err := url.Parse(v)
 			if err != nil {
 				return nil, fmt.Errorf("parse uri: %w", err)
 			}
 			session.URI = u
-			// TODO(otl): what do we expect next?
+			onext = fchars[2:]
 		case "e":
 			addr, err := parseEmail(v)
 			if err != nil {
 				return nil, fmt.Errorf("parse email: %w", err)
 			}
 			session.Email = addr
-			// TODO(otl): what do we expect next?
+			onext = fchars[3:]
+		case "p":
+			session.Phone = v
+			onext = nil
 		default:
-			return &session, fmt.Errorf("unsupported field %q", k)
+			return nil, fmt.Errorf("expected one of %v, found %q", onext, k)
 		}
 	}
 	return &session, sc.Err()
diff --git a/sdp/sdp_test.go b/sdp/sdp_test.go
@@ -1,6 +1,9 @@
 package sdp
 
 import (
+	"net/mail"
+	"net/url"
+	"reflect"
 	"strings"
 	"testing"
 )
@@ -21,11 +24,30 @@ m=audio 49180 RTP/AVP 0
 m=video 51372 RTP/AVP 99
 c=IN IP6 2001:db8::2
 a=rtpmap:99 h263-1998/90000`
+	want := Session{
+		Name: "Call to John Smith",
+		Origin: Origin{
+			Username:    "jdoe",
+			ID:          3724394400,
+			Version:     3724394405,
+			Network:     "IN",
+			AddressType: "IP4",
+			Address:     "198.51.100.1",
+		},
+		Info: "SDP Offer #1",
+		URI: &url.URL{Scheme: "http",
+			Host: "www.jdoe.example.com",
+			Path: "/home.html",
+		},
+		Email: &mail.Address{"Jane Doe", "jane@jdoe.example.com"},
+		Phone: "+1 617 555-6011",
+	}
 	session, err := ReadSession(strings.NewReader(s))
 	if err != nil {
 		t.Fatalf("read session: %v", err)
 	}
-	if session.Name != "Call to John Smith" {
-		t.Errorf("bad name bla bla TODO")
+	if !reflect.DeepEqual(*session, want) {
+		t.Errorf("got %+v\nwant %+v\n", *session, want)
 	}
+	t.Errorf("TODO still not parsing all fields")
 }